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Objective@#To analyze the MRI characteristics and pathological features of the condylar cyst like lesions in temporomandibular joint (TMJ).@*Methods@#The study was conducted retrospectively on TMJ images from 14 patients (2 males, 12 females, aged 10-71) who underwent MRI examinations, from January 2015 to December 2017 at Center for TMD and Orofacial Pain, Peking University School and Hospital of Stomatology including 2 patients with pathological results. The signals of the lesion, condylar bone and disc-condyle relationship were evaluated.@*Results@#Cyst like lesions of 15 condyles from 14 patients were analyzed. All of the lesions showed hypersignal on T2WI (12/12), while most of them showed hypersignal on T1WI (8/11) and PDWI (11/12). Mostly the lesions were surrounded by hyposignal linear margin (12/15), with normal condylar bone signal (13/15). Disk displacement with reduction was discovered in 3 joints, while disk displacement without reduction was discovered in 8 joints and 4 joints had normal disk-condyle relationships. The pathological components of cyst like lesions included cartilage, loose connective tissue, hemorrhage and bone tissue.@*Conclusions@#Differed from those of large joints like hips or knees, MRI characteristics of cyst like lesions of condyle in TMJ exhibited hypersignal imaging in both T1WI and T2WI, indicating that the components of cyst like lesions included granulation tissue, not fluid.
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Diagnosis and treatment of temporomandibular disorders (TMD) have been paid attention greatly by dentists in clinic. Imaging is the most important method for dentists to diagnose TMD correctly. Cone-beam CT (CBCT) and MRI have been demonstrated superiority and necessity that contribute to correctly diagnosis, early diagnosis and follow-up patients. However, there are several significant problems required for professional agreement: the procedures for CBCT and MRI examination need to be standardized; dentists have to be trained regularly for the knowledge of the imaging diagnosis of TMD; it should be emphasized that patient history and clinical examination are much more important for diagnosis, imaging is only a supplement and should not be over used.
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Objective@#To analyze the radiological characteristics of the condylar bone in patients with anterior disc displacement without reduction of temporomandibular joint using cone-beam CT (CBCT), and to further investigate the clinical factors possibly associated with the early-stage osteoarthritic changes.@*Methods@#Two hundred and four individuals (≤30 years old) diagnosed as unilateral anterior disc displacement without reduction (disease duration≤1 year) were recruited. CBCT images of bilateral condyles were independently evaluated by two assessors and documented. Correlation between the early-stage osteoarthritic (OA) changes and gender, age, disease duration and mouth opening were analyzed using SPSS 21.0 software.@*Results@#About sixty percent were presented with OA changes in the symptomatic joints, and most of them (47.1%) (96/204) were early-stage OA changes characterized by loss of continuity of articular cortex (Ⅰ) and/or surface erosion (Ⅱ). Logistics regression analyses indicated that disease duration (P =0.000) and mouth opening (P =0.002) were correlated significantly with early-stage OA changes.@*Conclusions@#Disc displacement without reduction was closely related to OA occurrence. OA changes occurred in more than half of the patients after one month of the joint locked and more possibly in patients with increased mouth opening.
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<p><b>OBJECTIVE</b>To explore the expression of purinergic p2X4 receptor (P2X4R) in trigeminal ganglion of rats after occlusal interference. Investigation of peripheral receptor mechanism of occlusal interference-induced masticatory muscle pain will aid the development of drug intervention against this condition.</p><p><b>METHODS</b>Experimental occlusal interference was established by application of 0.4 mm metal crown to the upper right first molar of male Sprague-Dawley rats. Real-time PCR assay was used to investigate P2X4R mRNA level in trigeminal ganglion in rats with occlusal interference for 3, 7, 10 and 14 days and in control rats without occlusal interference (n=5 in each). Retrograde labelling combining immunofluorescence was performed to evaluate the percentage of P2X4R-positive cells in masseter afferent neurons (n=5 in each group). Graded concentrations of P2XR antagonist TNP-ATP (0.1, 10, 125, 250, 500 μmol/L) or saline (n=5 in each group) was administrated in right masseter and the mechanical sensitivity of bilateral masseters was measured before occlusal interference application, before the injection, and 30 min as well as 60 min after the injection.</p><p><b>RESULTS</b>Compared with control rats (P2X4R mRNA: right side: 1.00±0.26, left side: 0.94± 0.21; percentage of P2X4R-positive masseter afferents: right side: [64.3±6.3]%, left side: [67.7±5.8]%), the level of P2X4R mRNA in bilateral trigeminal ganglia (right side: 5.98±3.56; left side: 5.06±2.88) of rats with occlusal interference for 7 days up-regulated (P<0.01) and the percentage of P2X4R-positive masseter afferent neurons(right side: [81.7±1.5]%; left side: [82.9±2.3]%) increased (P<0.05). Local administration of 10, 125, 250, 500 μmol/L TNP-ATP increased the mechanical withdrawal threshold in masseter 30 min after injection, compared with those before injection (P<0.05).</p><p><b>CONCLUSIONS</b>Increased expression of trigeminal P2X4R involves in the development of occlusal interference-induced masseter hyperalgesia.</p>
Subject(s)
Animals , Male , Rats , Adenosine Triphosphate , Pharmacology , Dental Occlusion , Hyperalgesia , Masseter Muscle , Masticatory Muscles , Purinergic P2X Receptor Antagonists , Pharmacology , RNA, Messenger , Metabolism , Rats, Sprague-Dawley , Real-Time Polymerase Chain Reaction , Receptors, Purinergic P2X4 , Genetics , Metabolism , Time Factors , Trigeminal Ganglion , MetabolismABSTRACT
Objective:To investigate the effect of segmental Le FortⅠosteotomy and bilateral sagittal split ramus osteotomy ( BSSRO ) on the condyle position in skeletal class Ⅲ malocclusion patients . Methods:In this retrospective study , 19 patients with skeletal class Ⅲmalocclusion who met the inclu-sion criteria were enrolled .All the patients underwent the segmental Le FortⅠ osteotomy and BSSRO . Cone beam computed tomography ( CBCT) scans were performed in the following phases:T1:within one week before the surgeries;T2:within one week post-surgery;T3:three months post-surgery;T4:6 to 14 months post-surgery .The posterior spaces , anterior spaces and the superior spaces of the bilateral tem-poromandibular joints were measured according to the Kamelchuk method respectively .The fossa ratios of the condyle and the distribution of the condyle positions related to the glenoid fossa ( anterior , concentric and posterior position ) were calculated .The results were analyzed statistically .Results:The posterior space , the anterior space and the superior space of bilateral temporomandibular joints in T 2 phase [ right:(2.78 ±1.23) mm, (2.47 ±0.89) mm, (3.07 ±0.85) mm; left: (2.93 ±0.83) mm, (2.69 ± 1.14) mm, (3.44 ±1.16) mm] showed significantly larger spaces than those in T 1 phase [right:(1.81 ±0.95) mm, (1.65 ±0.55) mm, (2.13 ±0.52) mm;left:(2.12 ±1.05) mm, (1.79 ±0.59) mm, (2.15 ±0.93) mm],in T3 phase [right:(2.08 ±1.25) mm, (1.79 ±0.68) mm, (1.80 ±0.76) mm;left: (2.05 ±0.75) mm, (1.99 ±0.94) mm, (2.14 ±0.71) mm] and in T4 phase [right:(1.94 ±0.77) mm, (1.81 ±0.69) mm, (2.05 ±0.69) mm;left:(1.89 ±0.69) mm, (1.80 ±0.61) mm, (2.19 ±0.75) mm], P0.05).The fossa ratio and the condyle position related to the glenoid fossa had no significant difference in all the four phases (P>0.05).The results suggested that the condyle moved downward in T 2 phase and changed to the original pre-surgery position in T3 phase, then keot stable in T4 phase.Conclusion:Segmental Le FortⅠ osteotomy and BSSRO caused significant and transient changes of the condyle position in skeletal class Ⅲmalocclusion patients . However , the condyle tended to move back to the original pre-surgery position and might keep stable .
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Objective:To investigate the peripheral mechanism by studying the histological changes of masseter muscles using HE stains and substance P(SP) and protein gene product 9.5(PGP9.5) immunohistochemical stains.Methods: Fifteen male Sprague-Dawley were randomly assigned into occlusal interference group(n=12) and control group(n=3).In occlusal interference group,0.4 mm thick crowns were bonded to the rats'first molar of the maxillary.In the control group,rats were anesthetized and mouths were forced open for about 5 min but restorations were not applied.1,5,10,and 21 d after 0.4 mm occlusal alteration treatment,mechanical pain thresholds of bilateral masseter muscles were quantitatively measured by modified electronic anesthesiometer in control group and occlusal interference group.The rats were euthanized by transcardiac perfusion after deep anesthetization at different time points.The paraffin sections of masseter muscles were made and processed for HE,SP,and PGP9.5 immunohistochemical staining.Results: Decreased head withdrawal threshold to mechanical pressure was detected in masseter muscles on both sides following occlusal interference.Histological stains of masseter muscles presented intact following occlusal interference,and no inflammatory cells were observed in both sides.Intensely stained PGP9.5 was observed at 1 d in occlusal interference groups and maintained until the end of the experiment.SP expression was the most obviously increased at 5 d in both sides and gradually decreased to the level of control.Conclusion: Experimental occlusal interference-induced masticatory muscle pain is associated with peripheral sensitization of nociceptive neurons rather than muscle damage and inflammation.
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<p><b>OBJECTIVE</b>To study the methodological techniques in measuring the severity of temporomandibulr disorders (TMD) and in evaluating the effectiveness of therapies in clinic.</p><p><b>METHODS</b>Both Fricton's Craniomandibular Index (CMI) and Helkimo's Clinical Dysfunction Index were calculated from 60 TMD patients. Inter-rater reliability was tested to assess the consistency in use between different examiners. Fricton's CMI was used to assess the clinical improvement after accepting a treatment in 21 TMD patients diagnosed as acute disk displacement without reduction.</p><p><b>RESULTS</b>Correlation Coefficient for inter-rater reliability in two groups was 0.879 and 0.939 respectively for Fricton's CMI and 0.744 and 0.838 for Helkimo Clinical Dysfunction Index. Fricton's TMJ dysfunction index was decreased from 0.337 to 0.021 (P < 0.001) and Fricton's CMI was decreased from 0.185 to 0.011 (P < 0.001) after the treatment in 21 TMD patients with disk displacement without reduction.</p><p><b>CONCLUSIONS</b>To avoid using subjective and descriptive report in assessment of the severity of TMD and the effectiveness of therapies, Fricton's CMI is recommended as an objective criteria which is simple in clinical use, and ease in scoring.</p>
Subject(s)
Adolescent , Adult , Child , Female , Humans , Male , Middle Aged , Severity of Illness Index , Temporomandibular Joint , Pathology , Temporomandibular Joint Disorders , Pathology , Temporomandibular Joint Dysfunction Syndrome , PathologyABSTRACT
<p><b>OBJECTIVE</b>To evaluate a new treatment method for temporomandibular joint acute disk displacement without reduction.</p><p><b>METHODS</b>Twenty-one patients diagnosed as acute anterior disk displacement without reduction were treated by manipulation with the aid of joint cavity extension followed by anterior repositioning splint. All and eleven of twenty-one patients were re-examined two weeks after insertion of splint and at the end of treatment (3 approximately 6 months later).</p><p><b>RESULTS</b>(1) Degree of maximum mouth opening was increased from 25.8 mm before treatment to 46.6 mm 2 weeks after, 48.1 mm at the end of treatment; (2) Mean pain level (VAS) dropped from 2.62 before treatment to 0.43 2 weeks after, 0.18 at the end of treatment; (3) Fricton's TMJ dysfunction index and craniomandibular index decreased from 0.337 and 0.185 respectively before treatment to 0.021 and 0.011 respectively 2 weeks after, 0.031 and 0.018 respectively at the end of treatment.</p><p><b>CONCLUSIONS</b>The treatment method should be considered for acute anterior disk displacement without reduction if medication and physical therapy failed to have disk successfully reduced.</p>
Subject(s)
Adolescent , Adult , Female , Humans , Male , Acute Disease , Joint Dislocations , Therapeutics , Manipulation, Orthopedic , Splints , Temporomandibular Joint Disorders , TherapeuticsABSTRACT
OBJECTIVE: To study the effects of occlusal trauma on the ultra-structure of synovial membrane and articular cartilage in rabbit's temporomandibular joints (TMJ). METHODS: TMJs from six rabbits with occlusal trauma and three control rabbits were studied by transmission electron microscopy. RESULTS: Degenerative changes in synovial membrane and articular cartilage of TMJ were induced following occlusal trauma. The structure of the articular surface was damaged, and chondrocytes in cartilage showed signs of degeneration. The synovial lining cells contained dense accumulations of vimentin intermediate filaments (IFs), which were especially prevalent in the cellular processes as well as paranuclearly. Microvilli on the synovial cell membrane were commonly seen. The "vermiform bodies" in the deeper interstitium of the synovial tissue were also found. Our findings of the punctate adherens between synovial lining cells were described in detail. CONCLUSIONS: The occlusal trauma is really a factor inducing degenerative changes of the TMJ.